You won't regret it. The general consensus is that this device is pretty amazing. Most people get great battery life (my average is 18hrs off charge 4-5hrs screen, mix in games voice calls etc), the ones that aren't, are suffering from standby drain (this may be due to the initial enabling of location tracking settings, discovered by Kev1000000, it's being tested). You will love active notifications, for such a seemingly simple feature... it's life changing. Always listening is also great, if you are like me and always wanted to use voice commands but was always left disappointed and frustrated, then you are in for a treat, this phone actually works extremely well, even in noisy conditions.
I also came from an sgs3, the difference is night and day, in battery, performance, comfort and how I interact with the device... I'm sure that you will not be disappointed.
Development is not quite here yet, but that's not necessarily a bad sign, this phone has been the best experience out of the box that I have ever had... Speaking as a recovering flashoholic, I am enjoying having a phone that is awesome right out of the gate. I feel that once 4.4 releases, we will see more activity, but with safestrap being released and root available, in sure things will be coming down the pipe line soon, but this phone doesn't really need it.
Sent from my XT1058 using XDA Premium 4 mobile app